A niche topic!
| Feature | isabelle-extreme | Isabelle/HOL | |---------|--------------------|---------------| | Logic | Minimal equational logic + fixed point | Higher-order logic | | Types | Simple types (no type classes) | Rich types with type classes | | Recursion | Via fixed point combinator ( fix ) | Primitive recursion, well-founded recursion | | Automation | None (manual rewriting only) | simp , auto , blast , sledgehammer | | Code generation | No | Yes (to ML, Scala, Haskell) | | Library | Empty | Thousands of theorems | isabelle-extreme
isabelle-extreme is a small object logic implemented inside Isabelle. Unlike HOL (Higher-Order Logic) or ZF (Zermelo-Fraenkel set theory), EXTREME is not designed for large-scale developments. Instead, it serves three critical roles: A niche topic